Redundant cues are also strong. So, for example, C is largely whitespace-insensitive and operator precedence can matter a lot. Consider "x+y*z". If you always spaced this "x+y * z" it would be the same to the parser but less clear to a human than spacing it "x + y*z" where you have used whitespace as a redundant cue to operator precedence.

Similarly, what makes C type declarators tricky for many is their "inverse nature" - "char *foo" means, applying the operator "*" to the identifier "foo" yields a base type "char". So, the "char* foo" form is literally creating a cue in the opposite direction of operator precedence just like "x+y * z" would. For just one indirection it's no big deal, but for things like "char *foo[]" and beyond it becomes more important. So, the "mis"-spacing "char* foo" sets people up for later conceptual failure.

This is in addition to the above point by @onre about multiple identifiers and @anacrolix's initial rather, ahem, pithy take. There is also another "where would ()s be redundant/unneeded" rationale (though this largely recapitulates the 2nd paragraph here). If you are looking for a catchphrase then maybe it could be "Don't space-against-syntax".